This is my trip to Paris for pre-wedding photo-shoot. Casa O is a small hotel with shared pantry - i wasn't aware of that when i do the booking. But the rooms inside are spacious, enough area for both of us to have our 29" luggage opened on the floor - which is not possible for many hotels in Paris which have tiny rooms. I have my wedding gowns and lots of stuff with me for this trip, but it wasn't a mess in the room.
The host is so sweet to have prepared roses and a quick note for us about our wedding trip, and room keeper is very cheerful and helpful throughout the whole time.
The location is good - only a few mins to metro, walking distance to restaurants and some bars.
Casa O is on the 2/F, a little bit difficult to find for your first time, but it's not a problem at all after you know where it is.
Overall - Good! I had a nice stay in Paris :)